Cold Weather Chugging

[c2cummin]

Just wondering if anyone else out there has problems with their car struggling to idle in really cold weather at start up? By cold I mean around -20 Celsius or colder.

I noticed last winter and this winter that if my vibe sits for a while outside in weather that cold that it'll chug pretty bad at the first couple of stops. Once the engine warms up it seems fine. I put some gas line antifreeze in and it seems to have gotten better so maybe I had some ice building up somewhere....

But ya...anyone else experience cold weather idle problems??

[vibrologist]

I noticed a few of those.

In fact it reminded me of the chugging the old Ford Windstar did. It chugged horribly when it was cold and cleared up when it was warm, no CEL was triggered at first. P0171 and P0174 appeared in time. This is what happened: Some rubber grommets on the intake manifold shrunk and caused a vacuum leak. While the computer was in open mode (using programmed values rather than sensor values) the fuel mixture was way to lean. The monitors are off in open loop and therefore did not trigger error codes. Once it was warm enough and went into closed loop using the sensor values the computer compensated for the vacuum leak and the engine ran fine. When the leaks got bad enough it triggered the error codes. After fixing the vacuum leak all was good.

On the Vibe the intake manifold gaskets seem not to last forever. I will replace mine when I do my tune up in Spring.
It is not likely that you have water in the fuel system. There is plenty ethanol in today's fuel to keep water from freezing anywhere in the fuel system.

[c2cummin]

I noticed a few of those.

In fact it reminded me of the chugging the old Ford Windstar did. It chugged horribly when it was cold and cleared up when it was warm, no CEL was triggered at first. P0171 and P0174 appeared in time. This is what happened: Some rubber grommets on the intake manifold shrunk and caused a vacuum leak. While the computer was in open mode (using programmed values rather than sensor values) the fuel mixture was way to lean. The monitors are off in open loop and therefore did not trigger error codes. Once it was warm enough and went into closed loop using the sensor values the computer compensated for the vacuum leak and the engine ran fine. When the leaks got bad enough it triggered the error codes. After fixing the vacuum leak all was good.

On the Vibe the intake manifold gaskets seem not to last forever. I will replace mine when I do my tune up in Spring.
It is not likely that you have water in the fuel system. There is plenty ethanol in today's fuel to keep water from freezing anywhere in the fuel system.

I actually had code P0171 pop up last winter a couple times. Only on extremely cold days and it never appeared again once I started using the gas line antifreeze. Never had any issues all summer either. If the light comes on again with that code I'll likely have it looked at.

I've read about the intake manifold gasket being the most common thing for that code to pop up. Looks easy enough to change I just never seem to have time...sigh....

[c2cummin]

I noticed a few of those.

In fact it reminded me of the chugging the old Ford Windstar did. It chugged horribly when it was cold and cleared up when it was warm, no CEL was triggered at first. P0171 and P0174 appeared in time. This is what happened: Some rubber grommets on the intake manifold shrunk and caused a vacuum leak. While the computer was in open mode (using programmed values rather than sensor values) the fuel mixture was way to lean. The monitors are off in open loop and therefore did not trigger error codes. Once it was warm enough and went into closed loop using the sensor values the computer compensated for the vacuum leak and the engine ran fine. When the leaks got bad enough it triggered the error codes. After fixing the vacuum leak all was good.

On the Vibe the intake manifold gaskets seem not to last forever. I will replace mine when I do my tune up in Spring.
It is not likely that you have water in the fuel system. There is plenty ethanol in today's fuel to keep water from freezing anywhere in the fuel system.

How long does the computer stay in open loop for? Just asking because it's hard for me to tell when it stops chugging since my commute to work is mostly highway driving and I get on the highway fairly quick from home and from work.

also want to add that the car has normal power once taking off, it doesn't seem to affect accelerating or anything. Fuel mileage seems a little less than normal but I always seem to get worse mileage in the winter.

[vibrologist]

It stays in open loop until the ECT sensor tells the computer that the engine is sufficiently warm. That should be shortly after the temp needle starts moving (guess).

Your observations are quite normal.
You could try leak detection after a cold start. Spray carb cleaner around the intake manifold where it sits at the engine. Try to get there from above and below. Maybe you need to disconnect the fan or shield the airflow with a card board. If spraying carb cleaner affects the idle you found the leak.
There are other methods to find vacuum leaks. Check with Youtube.

[c2cummin]

Update:

Engine light came on last week with code P0171:P. Intake gasket was indeed leaking. It was only leaking when car was cold, that's why it was chugging. Had it replaced and all is good. Even seem to have more power now!

[vibrologist]

Thanks for the update. That confirms that I have to replace my intake gasket as well. I can wait until it is warm outside. You have restored the power of your engine and the fuel consumption should come down a smidgeon.

[c2cummin]

Thanks for the update. That confirms that I have to replace my intake gasket as well. I can wait until it is warm outside. You have restored the power of your engine and the fuel consumption should come down a smidgeon.

I had read the most common problem on these with the lean code was the gasket but I had no real way of diagnosing it to do it myself. It didn't take the shop long to do and was around 200 bucks.

It does kind of suck considering the gasket is only 11 bucks.

They said the gasket was shrinking in severe cold weather and that's why it was chugging. Once the car warmed up everything would expand and the leak would seal itself.

I might change my spark plugs this summer/spring now too. I guess whichever cylinder was leaking would have been running hotter than the rest so they told me it might not be a bad idea to change the plugs shortly. That'll I'll just do myself though.....

[vibrologist]

I look for vacuum leaks by spraying a flammable liquid (MAF sensor cleaner, it's easy on plastics) at suspected areas while the engine idles. In this case you would have been doing this in extreme cold. Not having to do that was worth the money, I think.

When I fixed the Windstar it was late fall. People reported repair bills of about $800 to put in 8 grommets and a few gaskets that I purchased for about $50. That was worth it being cold for an afternoon.

On my wife's Ford Contour I found a leak using the spray can method. There was no CEL but the idle was rough. I sprayed around the intake and I noticed the idle stabilizing when I sprayed at a certain angle. But it was not where I aimed at. The leak was at the level of the oil pan. The spray just happened to go that far. There was a rubber hose that connected from the crank case to the intake, part of the PCV lines. $20 for the hose and I was done.

In a Mazda Protege it was the air intake hose. The cracks were plain to see. I wrapped it with duct tape.

Enjoy your ride. No one will blame you for avoiding frost bite!

[cptnsolo77]

I have this problem as well when it gets "cold" here in south Florida. The idle drops to about 500 RPM and feels like it wants to shut off. I changed the intake gasket and it didnt help. I never got any codes when this happened. Through extensive research on this site I narrowed it down to cleaning the Idle Air Control Valve, also known as the IAC valve. Being that these "cold" spells" dont last long here...lasts about one week out of the year, I havent put much importance on it.

[c2cummin]

I have this problem as well when it gets "cold" here in south Florida. The idle drops to about 500 RPM and feels like it wants to shut off. I changed the intake gasket and it didnt help. I never got any codes when this happened. Through extensive research on this site I narrowed it down to cleaning the Idle Air Control Valve, also known as the IAC valve. Being that these "cold" spells" dont last long here...lasts about one week out of the year, I havent put much importance on it.

Mine has a bit of a rough idle and I was wondering if cleaning the valve might help....I was going to try changing the plugs first though...

So did you end up not cleaning the valve since the cold spells or so short?

[cptnsolo77]

Yes...I havent done it yet. Check out these threads. This solved some members cold idle probs. I saved these links in my email so that I can refer to them when I finally get to it. They both have some great pics as well

viewtopic.php?f=17&t=36489&p=476353&hilit=iac#p476353" onclick="window.open(this.href);return false;

http://matrixowners.com/index.php?/topi ... ics-incld/" onclick="window.open(this.href);return false;